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Giorgio Tranchida, IAMC-CNR (Italy)
Adriana Bellanca, University of Palermo (Italy)
Massimo Angelone, ENEA (Italy)
Rodolfo Neri, University of Palermo (Italy)
Salvatore Mazzola, IAMC-CNR (Italy)
Bernardo Patti, IAMC-CNR (Italy)
Angelo Bonanno, IAMC-CNR (Italy)
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Results obtained from a geochemical high-resolution study carried out on box-core sediments from the Strait of Sicily permitted to reconstruct the spatial and temporal distribution of major and trace elements. The analysed samples were collected during the oceanographic cruises Bansic01, Ansic02, and Ansic03, onboard the Research Vessel "Urania" along three onshore-offshore transects in front of the towns of Sciacca, Gela, and Pozzallo (southern Sicilian coast). Sediments were dated by measuring radiometric activity of 210Pb by alpha spectrometry. The vertical distribution of heavy metals in the cores well records the effects of industrialization, intensive agricultural activities, and severe urbanization that affected the southern coast of Sicily since the begin of the 20th century and with an evident enhancement starting from around the 1960s. Different statistical algorithms applied to the geochemical dataset show a spatial variability of major and trace elements along the Sciacca transect that reflects the irregular morphology of the Adventure Bank. PCA and Cluster Analysis permitted to discriminate a lithogenic origin essentially for Cr, Cu, Co, V, and Zn and a source partially deriving from anthropogenic inputs for Sb, Cd, As, Pb, and Hg. Analysis of current circulation, supported by in situ hydrological observations (cruise Ansic04) along the southern Sicilian coast, provided a model for the Atlantic Ionian Stream circulation at the surface and detected the core of the Levantine Intermediate Water at depth. The oceanographic approach, by the reconstruction of dynamics and chemical-physic features of the water mass, is invoked to justify the higher sediment accumulation rate and high contents of some heavy metals in the sediments near the Pozzallo coast.
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